Function writeGoMod

packages/go/src/index.ts:761–825

* Writes a `go.mod` file in the specified directory. If a `go.mod` file * exists, then update the module name and any relative `replace` statements, * otherwise write the minimum module name. * @param workPath The work path; required if `goModPath` exists * @param goModPath The path to the `go.m

({
  destDir,
  goModPath,
  packageName,
}: {
  destDir: string;
  goModPath?: string;
  packageName: string;
})

 * @param packageName The module name to inject into the `go.mod`
 */
async function writeGoMod({
  destDir,
  goModPath,
  packageName,
}: {
  destDir: string;
  goModPath?: string;
  packageName: string;
}) {
  let contents = `module ${packageName}`;

  if (goModPath) {
    const goModRelPath = relative(destDir, dirname(goModPath));
    const goModContents = await readFile(goModPath, 'utf-8');

    contents = goModContents
      .replace(/^module\s+.+$/m, contents)
      .replace(
        /^(replace .+=>\s*)(.+)$/gm,
        (orig, replaceStmt, replacePath) => {
          if (replacePath.startsWith('.')) {
            let newPath = join(goModRelPath, replacePath);
            // path.join() strips the './' prefix when goModRelPath is
            // empty.  Go requires replacement paths without a version to
            // start with './' or '../', so restore the prefix when needed.
            if (!newPath.startsWith('.') && !newPath.startsWith('/')) {
              newPath = './' + newPath;
            }
            return replaceStmt + newPath;
          }
          return orig;
        }
      );

    // get the module name, then add the 'replace' mapping if it doesn't
    // already exist
    const matches = goModContents.match(/module\s+(.+)/);
    const moduleName = matches ? matches[1] : null;
    if (moduleName) {
      let relPath = normalize(goModRelPath);
      if (!relPath.endsWith('/')) {
        relPath += '/';
      }

      const requireRE = new RegExp(`require\\s+${moduleName}`);
      const requireGroupRE = new RegExp(
        `require\\s*\\(.*${moduleName}.*\\)`,
        's'
      );
      if (!requireRE.test(contents) && !requireGroupRE.test(contents)) {
        contents += `require ${moduleName} v0.0.0-unpublished\n`;
      }

      const replaceRE = new RegExp(`replace.+=>\\s+${relPath}(\\s|$)`);
      if (!replaceRE.test(contents)) {
        contents += `replace ${moduleName} => ${relPath}\n`;
      }
    }